Meetups, museums, lectures by visiting scholars, stops on book tours, concerts/plays/other performances, cultural festivals, interesting architectural sites, professional sports, restaurants, a wide variety of interesting neighborhoods within walk distance, ....
There’s nothing wrong with Fresno. Plenty of lovely people live there, and I’m sure there are all sorts of things happening all the time. It just doesn’t (to me at least) seem comparable to the Bay Area. As one example, Fresno State is a fine school, but it can’t compete with Berkeley and Stanford.
The population density is also relatively low, and it doesn’t seem like a very easy place to live without frequently using a car. (I end up using a car about once a month.) I really appreciate being able to walk to 3 different grocery stores within a 3 block radius, walk to 10 coffee/tea shops, walk to 100 restaurants of every imaginable type, walk to the park, walk to 2 library branches, walk to several little art galleries, walk to bakeries and fish markets, walk to all sorts of little shops, walk to the subway, ...